Measurement of the very rare K+→π+ννˉK^+ \to \pi^+ \nu \bar\nu decay

The decay K+→π+νν¯ , with a very precisely predicted branching ratio of less than 10−10 , is among the best processes to reveal indirect effects of new physics. The NA62 experiment at CERN SPS is designed to study the K+→π+νν¯ decay and to measure its branching ratio using a decay-in-flight technique. NA62 took data in 2016, 2017 and 2018, reaching the sensitivity of the Standard Model for the K+→π+νν¯ decay by the analysis of the 2016 and 2017 data, and providing the most precise measurement of the branching ratio to date by the analysis of the 2018 data. This measurement is also used to set limits on BR(K+→π+X ), where X is a scalar or pseudo-scalar particle. The final result of the BR(K+→π+νν¯ ) measurement and its interpretation in terms of the K+→π+X decay from the analysis of the full 2016-2018 data set is presented, and future plans and prospects are reviewed

Dose-Tracking Software: A Retrospective Analysis of Dosimetric Data in CT Procedures

The increasing use of ionizing radiation in healthcare is causing growing alarm about radiation protection of patients and the doses they receive during procedures. Radiation dose assessment for patients in radiodiagnostic procedures is the subject of interest in view of the recent Italian D.Lgs 31 July 2020, n. 101 (Decreto Legislativo 31 luglio 2020, n. 101) and one of its most important focuses is the prescription to provide patient exposure information as an integral part of the examination report. Dose monitoring systems are therefore essential for the collection of the dosimetric data. In order to analyse potential and critical issues of these software, different systems, adopted at the Antonio Cardarelli Hospital in Naples, were employed. Data extracted from the DoseWatch software (GE Healthcare) and Gray Detector (EL.CO. S.r.l. Healthcare Solutions, Italy) and relating to several protocols adopted for computed tomography (CT), were retrospectively analysed for the purpose of identifying critical issues in the data acquisition and recording phase, comparing with Italian nationwide diagnostic reference levels (DRLs), as provided for in regulatory provisions for radiation safety. Multiphase examinations were also included in this study. Once the distributions of volumetric CT Dose Index (CTDIvol) and dose-length product (DLP) were determined for each acquisition phase and total DLP (DLPtot) for each examination, the 25th, 50th and 75th percentiles were calculated for each distribution and then compared with the relevant Italian nationwide DRLs. In addition, to improve protocol optimization and dose reduction the magnitude of the CT acquisition settings chosen in each procedure was evaluated. In conclusion, these systems allow accurate analysis of radiation dose according to equipment and protocol over time. For the application of optimization measures, a constant use of the dose tracking software is required, which can be translated into actions on scan parameters and prospective data analysi

Measurement of the branching ratio and search for a CP violating asymmetry in the eta ---> pi+ pi- e+ e-(gamma) decay at KLOE

We have studied the eta→pi+pi-e+e-(gamma) decay using about 1.7 fb−1 collected by the KLOE experiment at the DAFNE phi-factory. This corresponds to about 72 millions eta mesons produced in phi radiative decays. We have measured the branching ratio, inclusive of radiative effects, with 4% accuracy: BR(eta→ pi-pi-e+e-(gamma) = (26.8 ± 0.9Stat. ± 0.7Syst.) × 10^−5. We have obtained the first measurement of the CP-odd pipi-ee decay planes angular asymmetry, Aphi = (−0.6±2.5Stat. ±1.8Syst.)×10^−2

ChPT test at NA48 and NA62 experiment at CERN

The new published measurements of the K± → π± γγ decay with minimum bias data samples collected by the two experiments NA48/2 and NA62 are discussed. The results include a model independent decay rate measurement and fits to Chiral Perturbation Theory (ChPT) description. The model independent branching ratio in the kinematic range z = (mγγ/mK)2 > 0.2, obtained by combining the NA48/2 and NA62 results, is BMI = (0.965 ± 0.63) × 10-6. The combined branching ratio in the full kinematic range assuming a ChPT description is BChPT = (1.003±0.056)×10-6. The uncertainties are dominated by the statistical errors. The data support the ChPT prediction for a cusp in the di-photon invariant mass spectrum at the two pion threshold and are in agreement with both O(p4) and O(p6) ChPT predictions

Measurement of sigma(e + e- ---> pi+ pi- gamma(gamma) and the dipion contribution to the muon anomaly with the KLOE detector.

We have measured the cross section σ(e+e− → pi+pi−>γ(γ)) at DAΦNE, the Frascati φ–factory, using events with initial state radiation photons emitted at small angle and inclusive of final state radiation. We present the analysis of a new data set corresponding to an integrated luminosity of 240 pb−1. We have achieved a reduced systematic uncertainty with respect to previously published KLOE results. From the cross section we obtain the pion form factor and the contribution to the muon magnetic anomaly from two-pion states in the mass range 0.592 < Mππ < 0.975 GeV. For the latter we find ∆pipiaμ=(387.2±0.5stat±2.4exp±2.3th)×10−10

Measurement of sigma(e + e- ---> pi+ pi- gamma(gamma)) and the dipion contribution to the muon anomaly with the KLOE detector.

We have measured the cross section σ(e+e− → pi+pi−>γ(γ)) at DAΦNE, the Frascati φ–factory, using events with initial state radiation photons emitted at small angle and inclusive of final state radiation. We present the analysis of a new data set corresponding to an integrated luminosity of 240 pb−1. We have achieved a reduced systematic uncertainty with respect to previously published KLOE results. From the cross section we obtain the pion form factor and the contribution to the muon magnetic anomaly from two-pion states in the mass range 0.592 < Mππ < 0.975 GeV. For the latter we find ∆pipiaμ=(387.2±0.5stat±2.4exp±2.3th)×10−10